Kinetic studies of anode materials for solid oxide fuel cell (SOFC)
Planar solid oxide fuel cells (SOFCs) were designed, fabricated, characterized and optimized in order to a) Develop a Nickel-free anode for SOFCs, b) Increase the total electrical conductivity of the crack-free composite in intermediate temperature zones, c) Establish defect chemistry formulations for the Mixed electrode systems, d) Confirm the stability issues of the anodes in reducing atmosphere, e) Weigh less compared to established YSZ-architectured predominant fuel cells, f) Incur less cost compared to YSZ predominant similar fuel cells, g) Produce more power output at low concentration of Hydrogen input, h) Optimize anode composition for best performance in the prevalent same size and temperature range and i) Validate the computational model. There's a huge demand of Nickel-free anode in the SOFC world due to several reasons like diminishing the weight, cost, resistivity and dissipation of energy. All the aforementioned major factors point individually towards the same direction - "development of novel anodes" from the materials' point of view operating at intermediate temperatures of 500-800oC or less. This study deals with developing a novel anode material conforming to all the above mentioned requirements in the same size and temperature range via modeling/validation, partial pressure and kinetic studies, microstructural analyses, diffraction techniques, polarization measurements, electro-chemical impedance and porosity studies. The average conductivity values found out to be 1.691, 0.0651, 0.0543 and 0.0148 s/cm respectively at 700, 600, 500 and 400OC in pure Hydrogen atmosphere. The avg. conductivity at 700OC is more than 5 times the value obtained from the GDC-CNF experiments and is believed to have been obtained with the better transport properties of the GDC-CNF matrix. Activation energy calculation were performed from the plot of ln(conductivity) vs. 1/T and found out to be .75 & .42 evs which are better comparable to the literature values by Zhu et.al.1 The bulk resistance (Rb) values got decreased dramatically in pure Hydrogen atmosphere from 2.169(400 OC) to 0.019(700 OC) ohms.